Hole saw blade

ABSTRACT

A hole saw has a cup shaped body with a base, and a cylindrical wall with an extending cutting edge. An arbor extends from base. A plurality of teeth are formed on the cutting edge. The teeth having a repeating first and second tooth form. The first tooth form has a rake face and relief face defining the cutting edge. The rake face and relief face are at a desired angle. A first gullet is continuous with the first rake face so that it has a desired depth. The second tooth form has a second rake face and second relief face. The faces are on a desired angle. A second gullet is continuous with the second rake face providing a second tooth height. The second tooth height is greater than the first tooth height.

FIELD OF THE INVENTION

The present invention relates to cylindrical cutters and, moreparticularly, to a hole saw tooth form.

BACKGROUND OF THE INVENTION

Holesaws have been used in the construction industry for drilling holesthat have a diameter of larger than 9/16 inch. Most commonly, holesawsare utilized for providing holes in electric panels and wood or metalstuds. The holes must be drilled accurately and quickly. This enablesthe workpiece to be smooth around the area of the drilled hole.

Various types of holesaws exist in the art. U.S. Pat. No. 5,803,678illustrates a holesaw. This holesaw includes raker teeth with aplurality of respective groups of saw teeth with each group having atooth displaced further from the side than the other. While this sawappears to work satisfactorily for its intended purpose, designersstrive to improve the art.

SUMMARY OF THE INVENTION

The present invention provides the art with a holesaw which reduces themoment and stress on the tooth. The present invention reduces the impacton the tooth by reducing the pitch between teeth. This also provides alarger number of teeth on smaller diameter bits. The present inventionprovide teeth with various gullet depth. The tooth pattern enables pairsof teeth to be provided with additional reinforcement.

According to one aspect of the invention, a holesaw comprises a cupshaped body with a base and a cutting edge. An arbor extends from thebase. The plurality of teeth are formed on the cutting edge. The teethinclude a first and second tooth form. The first tooth form has a firstrake face on an angle from about 5° to 12°. A relief face is adjacent tothe rake face to form a cutting edge. The relief face is at an angle ofabout 30° to 40°. A first gullet is continuous with the relief face. Thegullet has a desired depth such that the first tooth form has a firstheight. The second tooth form has a second rake face continuous with afirst gullet. The second rake face defines a rake angle from about 5° to12°. The second relief face is adjacent the second rake face to form acutting edge. The second relief face is on an angle from about 30° to40°. The second gullet is continuous with the second relief face. Thesecond gullet has a desired depth such that the second tooth form has asecond tooth height. The second tooth height is greater than the firsttooth height. Ordinarily, the first and second relief angles as well asthe first and second rake angles are the same. The cutting edges of thefirst and second tooth forms are substantially at the same height. Thefirst and second tooth forms form a repeating pattern with set or unsetor both teeth. Ordinarily, the teeth can be arranged so that they areset inside outside or inside outside with one or two raker teeth betweenthe inside and outside teeth.

According to the second aspect of the invention, a saw blade comprisesteeth having first and second repeating tooth forms. The first toothform has a first rake face on an angle from about 5° to 12°. A reliefface is adjacent to the rake face to form a cutting edge. The reliefface is at an angle of about 30° to 40°. A first gullet is continuouswith the relief face. The gullet has a desired depth such that the firsttooth form has a first height. The second tooth form has a second rakeface continuous with a first gullet. The second rake face defines a rakeangle from about 5° to 12°. The second relief face is adjacent thesecond rake face to form a cutting edge. The second relief face is on anangle from about 30° to 40°. The second gullet is continuous with thesecond relief face. The second gullet has a desired depth such that thesecond tooth form has a second tooth height. The second tooth height isgreater than the first tooth height. Ordinarily, the first and secondrelief angles as well as the first and second rake angles are the same.The cutting edges of the first and second tooth forms are substantiallyat the same height. The first and second tooth forms form a repeatingpattern with set or unset or both teeth.

From the following detailed description taken in conjunction with theaccompanying drawings and claims, other objects and advantages of thepresent invention will be come apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of a holesaw in accordance with the presentinvention;

FIG. 2 is a side elevational view of a portion of the cutting edge ofthe holesaw of FIG. 1;

FIG. 3 is a plan view of a tooth pattern in accordance with theinvention;

FIG. 4 is a second embodiment of a tooth pattern in accordance withpresent invention; and

FIG. 5 is a plan view of a third embodiment of a tooth pattern of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Turning to the figures, a holesaw is illustrated and designated with thereference numeral 10. The holesaw 10 includes a cup shaped body 12, anarbor 14, and a drill bit 16. The arbor 14 as well as the drill bit 16are like those conventionally used. The arbor 14 includes a bore toreceive the drill bit 16 in a conventional way.

The body member 12 includes a base 18, a cylindrical wall 20 and acutting edge 22. The base 18 includes an arbor aperture to receive thearbor 14. The cylindrical wall 20 can have a desired diameter and isusually formed such as by stamping with the base 18. The cutting edge 22is at the end of the wall 20 extending away from the base 18.

The cutting edge 22 includes a plurality of teeth 24. The teeth 24 havea first tooth form 26 and a second tooth form 28.

Turning to FIG. 2, an enlarged tooth form is illustrated. The firsttooth form 26 has a rake face 32 and a relief face 34. The rake face ison a rake angle of about 5° to 12°. Preferably, the rake angle is about10°. The rake face 32 has a tooth depth which is identified by thenumeral 36. The relief face 34 is defined by a relief angle of between30° to 40°, preferably, the relief angle is about 35°. The relief faceis continuous with a curve portion 38 of the gullet 40. The gullet leadsinto the second tooth form 28.

The first tooth form 26 has a desired included angle of about 38° to 55°at the tip. The tooth form 26 has an additional base area 44 whichincreases the mass of the tooth 26, which, in turn, increases thestrength of the tooth reducing the moment and stress in the tooth base44. The first tooth form gullet 42 has a radius defined by the numeral46. The first tooth form 26 depth and the gullet radius 46 define themaximum gullet depth or tooth height 48. The first pitch designated withthe reference numeral 50 is the distance between the tip of the secondtooth form 28 and the first tooth form 26

The first tooth form depth is a length from the tip of the tooth to thecurved portion of the gullet. The tooth depth has a length from about18% to 24% of the tooth height or maximum gullet.depth. Preferably, thetooth depth is about 21% of the tooth height or maximum gullet depth.

The gullet radius 46 has a length between about 53% to 65% of the lengthof the tooth height or maximum gullet depth. Preferably, the gulletradius 46 has a length of about between 53% and 54% of the length of thetooth height or maximum gullet depth. Also, the gullet radius is betweenabout 18% to 25% of the length of the first pitch 50. Preferably, thegullet radius 46 is about 21% of the pitch 50.

The second tooth form 28 has a rake face 62 which is on a rake angle offrom about 5° to 12°. Preferably, the rake angle is about 10°. The rakeface 62 has a tooth depth identified by the numeral 66. The relief face64 is defined by a relief angle of about 30° to 40°. Preferably, therelief angle is about 35°. The relief face is continuous with the curvedportion of the gullet 42.

The tooth form has a desired included angle of between 38° to 55° at itstip. The included angle is preferably about 45°. Also, the tooth has anenlarged root area 68. The enlarged root area 68 increases the strengthof the tooth. The increased strength reduces the moment and stress inthe tooth base.

The gullet 40 has a radius defined by the numeral 70. The tooth depth 66and the gullet depth 70 define the maximum gullet length or tooth length72. The pitch designated with the reference numeral 74 is the distancebetween the tip of the first tooth form and the second tooth form.

The second tooth form depth 66 is a length from the tip of the toothform 28 to the curved portion of the gullet 40. The tooth depth 66 has alength from about 30% to 40% of the tooth height or maximum gulletdepth. Preferably, the tooth depth is about 30% of the tooth height ormaximum gullet depth.

The gullet radius 70 has a length between about 55% to 65% of the lengthof the tooth height or maximum depth. Preferably, the gullet radius 70length is about 54% of the length of the tooth height or maximum gulletlength. Also, the gullet radius is between 10% to 25% the length of thepitch. Preferably, the gullet radius 70 is about 24% of the length ofthe pitch.

The repeating first tooth form second tooth form provides an increasedroot between adjacent large gullets 40. Thus, both teeth are reinforcedon the large root portion between the two adjacent large gullets 40.Thus, the small gullet 42 which is behind each of the large teeth wouldreinforce the base of that tooth when it is exposed to higher impacts.The repeating pitch which have a different size, reduces the impact onthe tooth during cutting. Also, the smaller pitch enables a largernumber of teeth per inch on the hole saw specifically with smallerdiameters.

FIGS. 3-5 illustrate various types of offset patterns. In FIG. 3, theteeth are unset raker, inside, unset raker, outside, unset raker. InFIG. 4, the pattern is offset inside, outside, inside, outside. In FIG.5, an additional pattern is shown. Here, the teeth pattern is unsetraker, unset raker, inside, unset raker, unset raker, outside, unsetraker, unset raker. Thus, while these provide optimal cutting, otherdesigns could be used.

The present hole saw increases the cuts per blade. Also, the presentholesaw decreases the cutting time to a particular material. Also, thepresent holesaw reduces the wear slope of the tooth of the saw blade.This means that during use, as the teeth wear, the slope or rake faceangle of the tooth form varies less than from its original slope.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A holesaw comprising: a cup shaped body having a base and a cuttingedge; an arbor extending from said base; a plurality of teeth on saidcutting edge, said teeth in a first and second tooth form, said firsttooth form having a first gullet continuous with a rake face on anglefrom about 5° to about 12°; a relief face adjacent said rake faceforming a cutting edge; said relief face at an angle of from about 38°to about 55°, and said gullet having a desired depth such that saidfirst tooth form has a first height; said second tooth form having asecond gullet continuous with said first relief face and a second rakeface, said second rake face defining a rake angle from about 5° to about12°; and a second relief face adjacent said rake face forming a cuttingedge, said second relief face on an angle of about 38° to about 55°, andsaid second gullet having a desired depth such that said second toothfrom has a second tooth height, wherein said second tooth height isgreater than said first tooth height.
 2. The holesaw according to claim1, wherein said first and second relief angle are the same.
 3. Theholesaw according to claim 1, wherein said first and second rake anglesare the same.
 4. The holesaw according to claim 1, wherein said firstand second tooth form cutting edges are at substantially from sameheight.
 5. The holesaw according to claim 1, wherein said first andsecond tooth form a repeating pattern.
 6. The holesaw according to claim5, wherein said repeating first and second tooth forms may be set orunset.
 7. The holesaw according to claim 6, wherein said repeating firstand second tooth forms are set inside and outside.
 8. The holesawaccording to claim 6, wherein said repeating first and second toothforms are set inside, outside separated by one or more unset rakerteeth.
 9. The holesaw according to claim 1, wherein a pitch betweenfirst and second tooth forms is greater than pitch between second andfirst tooth forms.
 10. A saw blade comprising: teeth having first andsecond repeating tooth form; said first tooth form having a first gulletcontinuous with a rake face on angle from about 5° to about 12°; arelief face adjacent said rake face forming a cutting edge; said reliefface at an angle of from about 38° to about 55°, and said relief face,said gullet having a desired depth such that said first tooth form has afirst height; said second tooth form having a second gullet continuouswith said first relief face and a second rake face, said second rakeface defining a rake angle from about 5° to about 12°; and a secondrelief face adjacent said rake face forming a cutting edge, said secondrelief face on an angle of about 38° to about 55°, and said secondgullet having a desired depth such that said second tooth from has asecond tooth height, wherein said second tooth height is greater thansaid first tooth height.
 11. The saw blade according to claim 10,wherein said first and second relief angle are the same.
 12. The sawblade according to claim 10, wherein said first and second rake anglesare the same.
 13. The saw blade according to claim 10, wherein saidfirst and second tooth form cutting edges are at substantially from sameheight.
 14. The saw blade according to claim 10, wherein said first andsecond tooth form a repeating pattern.
 15. The saw blade according toclaim 15, wherein said repeating first and second tooth forms may be setor unset.
 16. The saw blade according to claim 15, wherein saidrepeating first and second tooth forms are set left right left right.17. The hole saw according to claim 15, wherein said repeating first andsecond tooth forms are set inside and outside.
 18. The hole sawaccording to claim 10, wherein said repeating first and second toothforms are set inside, outside separated by one or more unset rakerteeth.